Method for preparing amorphous iron oxide hydroxide

Abstract

A method for preparing amorphous iron oxide hydroxide, comprising following steps: (1) preparing a ferrous salt solution with solid soluble ferrous salt; (2) preparing a hydroxide solution; (3) mixing said hydroxide solution and said ferrous salt solution in a co-current manner for reaction at an alkali ratio of 0.6˜0.8 and a reaction temperature not exceeding 30° C.; (4) after the reaction in step (3) is finished, yielding a first mixture, then charging said first mixture with a gas containing oxygen for oxidation, and controlling the first mixture at a pH value of 6˜8 until the oxidation is finished to yield a second mixture; and (5) filtering, washing with water and drying said second mixture obtained in step (4) to yield the amorphous iron oxide hydroxide.

The invention claimed is: 
     
       1. A method for preparing amorphous iron oxide hydroxide which comprises following steps:
 preparing a ferrous salt solution with a solid, soluble ferrous salt, 
 preparing a hydroxide solution, 
 forming a first mixture by mixing and reacting the hydroxide solution and the ferrous salt solution in a co-current manner by controlling the ferrous salt solution feeding speed to 200-300 ml/min. and the hydroxide solution feeding speed to 50-60 ml/min.; by controlling the reaction temperature to not more than 30° C. and by controlling the alkali ratio of the hydroxide solution and the ferrous salt solution to 0.6 to 0.8, 
 oxidizing the first mixture with an oxygen-containing gas at a pH of 6-8 to yield a second mixture, and 
 filtering, washing with water and drying said second mixture to obtain the amorphous iron oxide hydroxide. 
 
     
     
       2. The method of  claim 1 , wherein the hydroxide is a hydroxide of group IA or group IIA elements. 
     
     
       3. The method of  claim 2 , wherein the ferrous salt solution has a concentration of 1.3-1.8 mol/L, and the hydroxide solution has a concentration of 4-6 mol/L. 
     
     
       4. The method of  claim 2 , wherein the drying is carried out at a temperature not exceeding 90° C. 
     
     
       5. The method of  claim 2 , wherein water is added to the first mixture before oxidizing the first mixture with the oxygen-containing gas. 
     
     
       6. The method of  claim 1 , wherein the ferrous salt solution has a concentration of 1.3-1.8 mol/L, and the hydroxide solution has a concentration of 4-6 mol/L. 
     
     
       7. The method of  claim 1 , wherein the pH of 6-8 is achieved by adding a further amount of hydroxide solution. 
     
     
       8. The method of  claim 7 , wherein the further amount of hydroxide solution has a concentration of 4-6 mol/L and a feeding speed of 10-20 ml/min. 
     
     
       9. The method of  claim 7 , wherein the alkali ratio of the hydroxide solution, including that mixed with the ferrous salt solution and that added for achieving the pH of 6-8, to the ferrous salt solution is 1.05-1.25. 
     
     
       10. The method of  claim 7 , wherein the drying is carried out at a temperature not exceeding 90° C. 
     
     
       11. The method of  claim 7 , wherein water is added to the first mixture before oxidizing the first mixture with the oxygen-containing gas. 
     
     
       12. The method of  claim 8 , wherein the alkali ratio of the hydroxide solution including that mixed with the ferrous salt solution and that added for achieving the pH of 6-8, to the ferrous salt solution is 1.05-1.25. 
     
     
       13. The method of  claim 8 , wherein the drying is carried out at a temperature not exceeding 90° C. 
     
     
       14. The method of  claim 9 , wherein the oxidizing is conducted for 10-15 h. 
     
     
       15. The method of  claim 9 , wherein the drying is carried out at a temperature not exceeding 90° C. 
     
     
       16. The method of  claim 1 , wherein the drying is carried out at a temperature not exceeding 90° C. 
     
     
       17. The method of  claim 1 , wherein water is added to the first mixture before oxidizing the first mixture with the oxygen-containing gas. 
     
     
       18. The method of  claim 1 , wherein the oxygen containing gas is air, and the air is added in an amount of not less than 700 L/h. 
     
     
       19. The method of  claim 12 , wherein the drying is carried out at a temperature not exceeding 90° C. 
     
     
       20. The method of  claim 12 , wherein the oxidation is conducted for 10-15 h.